Evidence Link logo: the letter E inside a blue diamond
Evidence Link

Evidence connected.
History traceable.
Integrity verifiable.

Evidence Link is a cryptographic evidence service for any record that has to hold up. Inspections, audits, repairs, approvals, assessments: whatever the work is, every event is sealed the moment it is recorded, chained to the event before it, checkpointed with a signature and a Bitcoin anchored timestamp, and exportable as one file that anyone you authorize can verify independently.

What it keeps

A subject can be anything with a history worth proving: a website, a building, a vehicle, a device, a property, a process. Evidence Link keeps the same three things for all of them.

Events

A timeline that cannot quietly change

Every event records who acted, what happened, when the source says it happened, and when Evidence Link sealed it. History is append-only: corrections arrive as new events, never as edits.

Artifacts

Originals, preserved byte for byte

Reports, photos, exports, and documents are stored as originals under their own fingerprints. What was sealed is exactly what comes back.

States

Before and after, proven

Versioned snapshots describe the state of a subject at each step. The change between any two snapshots is computed, not narrated: what appeared, what resolved, what is still open.

The cryptography

No proprietary black box. Evidence Link is built from standard, publicly understood methods, applied in a strict order.

Method 1

SHA-256 fingerprints

Every artifact is hashed with SHA-256 and stored under its own digest. Change a single byte and the fingerprint no longer matches, so altered evidence identifies itself.

Method 2

Canonical manifests

Each event carries a manifest of its artifacts, serialized as canonical JSON: sorted keys, fixed encoding. The same content always produces the same hash, on any machine, at any time.

Method 3

Hash chains

Every event's hash is computed over the event itself plus the hash of the event before it, per subject. Delete, reorder, or rewrite an entry and the chain breaks at exactly that point.

Method 4

Signed checkpoints

The head of every chain is periodically signed with Ed25519, and copies of the signed checkpoints are anchored outside the database. Even replacing the whole database cannot quietly rewrite a signed history.

Method 5

Offline verification

Every export ships with a small, dependency-free verifier. Counsel, an auditor, or an independent expert can recompute every fingerprint, link, and signature locally. No account, no network, and no trust in Evidence Link required.

Method 6

Bitcoin anchored timestamps

Every signed checkpoint hash is submitted to the Bitcoin blockchain through OpenTimestamps. Only the hash ever leaves our servers, never the evidence. Once the anchor confirms, anyone can prove the checkpoint existed by that block time, without taking our word for it.

Export

The Case File

One download holds the originals, the full event history, the state snapshots and their diffs, attestations, the signed checkpoint, and the verifier. Helpful and adverse records alike, in full.

What this proves, and what it does not. The cryptography proves the record you hold is the record that was sealed, complete and unaltered since sealing. It does not prove the original observations were correct, and it is not a certification of anything. Relevance and admissibility are questions for legal counsel.
Private by design. Evidence is never public. Records are visible only to their owner and the people they authorize, exports are scoped and logged, and public pages show status only.

In production: Outfielder

Evidence Link powers the record behind Outfielder, where it seals accessibility assessments, fixes, and verifications for businesses, and the public face of each record is a status page at AAccessibility.com. Same ledger, same methods, ready for the next field that needs its history to hold up.